Difference in Macroscopic Morphologies of Amylosic Supramolecular Networks Depending on Guest Polymers in Vine-Twining Polymerization.

Saya Orio,Takuya Shoji,Kazuya Yamamoto,Jun-Ichi Kadokawa

doi:10.3390/polym10111277

Abstract

Amylose, a natural polysaccharide, acts as a host molecule to form supramolecular inclusion complexes in its enzymatically formation process, that is, phosphorylase-catalyzed enzymatic polymerization using the α-d-glucose 1-phosphate monomer and the maltooligosaccharide primer, in the presence of appropriate guest polymers (vine-twining polymerization). Furthermore, in the vine-twining polymerization using maltooligosaccharide primer-grafted polymers, such as maltoheptaose (G7)-grafted poly(γ-glutamic acid) (PGA), in the presence of poly(ε-caprolactone) (PCL), the enzymatically elongated amylose graft chains have formed inclusion complexes with PCL among the PGA main-chains to construct supramolecular networks. Either hydrogelation or aggregation as a macroscopic morphology from the products was observed in accordance with PCL/primer feed ratios. In this study, we evaluated macroscopic morphologies from such amylosic supramolecular networks with different guest polymers in the vine-twining polymerization using G7-grafted PGA in the presence of polytetrahydrofuran (PTHF), PCL, and poly(l-lactide) (PLLA). Consequently, we found that the reaction mixture using PTHF totally turned into a hydrogel form, whereas the products using PCL and PLLA were aggregated in the reaction mixtures. The produced networks were characterized by powder X-ray diffraction and scanning electron microscopic measurements. The difference in the macroscopic morphologies was reasonably explained by stabilities of the complexes depending on the guest polymers.

Highlights

Polysaccharides and polypeptides, the major classes of biopolymers, exhibit specific biological functions in nature, in accordance with their controlled primary structures, as well as regular higher-order structures [1,2,3]
The macroscopic morphologies from the supramolecular networks produced by the vine-twining polymerization using G7 -grafted poly(γ-glutamic acid) (PGA) in the presence of PCL were dependent on the PCL/primer (G7 ) feed ratios [35]
We found that the supramolecular networks produced by the vine-twining polymerization using G7 -grafted PGA macroscopically constructed the hydrogel or aggregate depending on the guest polymers for complexation with amylose graft chains as cross-linking points

Summary

Introduction

Polysaccharides and polypeptides, the major classes of biopolymers, exhibit specific biological functions in nature, in accordance with their controlled primary structures, as well as regular higher-order structures [1,2,3]. Amylose, which is a natural polysaccharide composed of glucose (G) repeating units, is known to form a regularly controlled double helical assembly in water [4,5], owing to α(1 → 4)-glycosidic arrangement in the G chain. Hybrid systems from several kinds of biopolymers are present in nature, such polysaccharide-protein (or peptide) conjugates as proteoglycans/peptidoglycans or glycoproteins [6,7,8,9]. Artificial saccharide-peptide conjugates can be expected as new bio-related functional materials, which have a potential for practical applications in biomedical and tissue engineering fields. Because biopolymers are composed of a wide variety of unit structures linked through controlled arrangements and contain functional groups such as hydroxy, amino, and carboxy groups, their chemical synthesis with well-defined structure generally requires multiple procedures.

Methods

Results

Conclusion